Add supported OS version to documentation

[jniggemann]

Documentation (prerequisites.md) states:

...
Ubuntu
Debian
...
Pi-hole only supports actively maintained versions of these systems.

At the time of writing, this would be Debian 13 (aka Trixie). Reading on the forums, it seems pihole does not yet officially support Trixie. It would be beneficial to let users know.

At least for Debian this should not create a lot of work, as Debian Stable only changes every ~2 years...

[yubiuser]

Support is on it's way:
pi-hole/pi-hole#6382

[jniggemann]

Congratulations to the team, that's great to hear!

Should we add this the supported OS' versions nontheless?
Edit: Just saw this is readily available in the tests.

Perhaps we could add that info to the installation documentation, along the lines "has been tested and should work on (if not, please open an issue)"

[yubiuser]

Should we add this the supported OS' versions nontheless?

I don't think so. We changed it from explicitly naming supported versions to

Pi-hole only supports actively maintained versions of these systems.

As we always forgot to update the text which led to a confused users.
I'd like to keep it as it is now - if the OS itself is maintained, users should get help from us to install Pi-hole - independently from what the (maybe outdated) docs say.